How did pirates navigate 400 years ago

Navigation was the toughest challenge that those who ventured out into the open seas faced. However, in this regard, pirates were experts in navigation during their days, and they did it all without a GPS. Even in their time, they were advanced, using the unique technology of the time and navigation tools. They were not restricted to the standard map and the telescope, and that made their voyages quite precise and also efficient. In this article, we’re going to explore further the technology that got used in the Golden Age of Pirates.


First, let’s start with a description of what an astrolabe is. It is a two-dimensional model of the celestial sphere. In the olden times, astrolabes were inscribed into brass disks, each part of the celestial sphere precisely captured. The origin of the name comes from the Greek words Astron and lambanien. When you put the two together, the words refer to “one who catches the heavenly bodies.”

The astrolabe during the time was a multifunctional device that was loved for both its effectiveness in navigation and portability. These gadgets enable pirates to make some accurate measurements. These included the ability to tell the position of celestial objects and measure the time of night by figuring out the altitude of the sun. They were also able to use the same approach to determine the altitude of any object on the horizon. Additionally, they could know what time of the day, month, and the year it was, and also determine their current latitude while at sea.


Astrolabes were available even before the 16th century though in a more primitive form. It is assumed that Hipparchus of Nicaea (190-120BC), a Greek astronomer, mathematician, and geographer, came up with them. He is considered the father of trigonometry, but he is better known for his accidental discovery of the equinox. By the time the world approached The Middle Ages and well into the 16th century, the astrolabe had experienced a lot of modification and was then considered a sophisticated instrument.

Pirates could use it to cross the vast Oceans of Earth with the astrolabes. The navigations were possible by using the sun, North Star, and the line on the horizon. Also, it was through measuring the altitude above the horizon that helped sailors keep their course for 200 years.

Diptych Dial

A diptych dial is a sundial instrument that first came into being in the 15th and 16th centuries in Nuremberg, Germany. It was set apart for the wealthy who could afford them. A few families made them in one area. It is used for telling time through the shadows cast by the sun and direction too. The name comes from the fact that the instrument has two hinged leaves that open up as a book does. The diptych dial has a string attaching both leaves that acts as a gnomon. A gnomon is the part of the dial that casts a shadow.


When you want to use the diptych dial to tell the time, you place it on a horizontal surface, ensuring both the compass built into the inside of the lower leaf and the gnomon is pointing to the true north. As the sun moves, it’s able to cast a shadow, falling on the numbers engraved on the leaf. It would tell the local time of where the sailors or travelers where. Additional features for telling time were smaller dials on the upper part of the lower leaf that could be used to show the Italian hours and Nuremberg hours depending on where you were.

Indicating the latitude was also a useful feature for a traveling merchant to have. There were different latitudes of various European cities engraved on the inner side of the upper leaf. It was helpful to have because the height of the sun in the sky varies along the different latitudes. You can also tell the time at night and the wind’s direction.


A lodestone is a type of mineral magnetite. What makes it different from other magnetite is that it not only possesses magnetic properties but also shows a distinct north-south polarity. They come from metamorphic rocks that can be found around the world though they are rare. The fact that lodestones occur naturally means they have been in use for thousands of years. Their first mention of them was by the Greek philosopher Thales of Miletus, who presumed that the lodestone possessed a soul.


However, it was the Chinese that learned that the magnetite could be used as primitive compasses that could tell the cardinal directions. From there, many explorers took up the lodestone as a tool that could help them the directions and thus allowing them to explore the globe. A current scientific theory explains that lodestones get their magnetism when struck by lightning, which gives it its magnetism.


As we know, the compass is an instrument that shows the direction. It is also used for orientation and navigation relative to where you are geographical with the cardinal points. Most of the time, the compass was found on gimbals, which allowed the needle to find the magnetic north. The first known compasses got lin the Chinese dynasty of Han (202 BC- 220AD), where they were made of lodestone. The iron needle was able to perform a similar function as the lodestone because compass makers would magnetize it by striking them with a lodestone.

Modern compasses use the degree system, where they cardinal points are instead 0 degrees to 360 degrees. In the past, where were alternately divided into cardinal points with north, east, south, and west being used to tell the exact location when navigating. In China, they divided them up into 24 points and in Europe 32 points around the compass. The earliest use of the compass in navigation and orientation is named in the Chinese Song Dynasty (960-1279 AD).



The patent for the first telescope was in 1608 by Hans Lippershey, a Dutch eyeglass maker. From there, more sophisticated versions of the same came about that revolutionized navigation for sailors, pirates included. It was the likes of Sir Isaac Newton, Edwin Hubble, and Galileo Galilei that all came together, over time, to develop one of the most advanced pieces of technology known to man. However, in its humble beginnings, the telescope was only able to magnify an image up to three times.

It was Galileo that upped the magnifications to about 20 times. Historically, he is also considered to be the first person to point the telescope skyward and make out the craters on the moon, the moon’s phases in detail, and was able to describe the Milky Way too. It was through the use of the same telescope that Galileo discovered the rings of Saturn and the moons of Jupiter. After, Isaac Newton came up with the Reflector telescope in 1668, which proved to be advantageous over existing models primarily because they were cheaper to build.

After, several other people came after to finally give us the Pirate’s telescope that they used to scout lands from a distance. Seamen also used them to look into the horizon and even the celestial sky to determine if they were headed in the right direction or where they needed to navigate away from obstacles.



The name octant comes from the Latin name for eight-part of a circle, which is known as an octans. It gets this name from the fact that the instrument’s arch is indeed an eighth of a circle. Though it is John Hadley and Thomas Godfrey who get independent credit for the invention of the octant, it is said that it was Isaac Newton who came up with the basis of it in 1699- the reflecting quadrant. How the octant works are that it is an instrument that uses mirrors to reflect the path of light. When you look through it, the angle measured doubles.

The octant works similarly to a modern-day sextant. It is also a reflecting navigation instrument that you can use to measure the angular distance that is between two objects within sight. That was thanks to the two mirrors that allow navigators to sight the sun and the horizon at the same time. The octant was thus used in celestial navigation. It worked by measuring the angle between the astronomical object in question and the horizon. When calculations got done, navigators could then estimate the latitude and the longitude. Sailors were thus able to sight the sun, moon, and stars from a moving ship.


These instruments were among the things that pirates and sailors alike could use to navigate the vast nothingness of the sea. Thanks to these inventions, they were able to traverse new territories and as a result, map out most of the world as we know it. It is, therefore, not a myth when you read about pirates having taken charge of the high seas 400 years ago.